Dowel pin sizing machine



Dec. 18, 1962' a. E. RICHARDSON nom. PIN sIzING MACHINE 5 Sheets-Sheet 1 Filed Jan. 13, 1960 De 18, 1962 a. E. RICHARDSON`l 3,068,916

DOWEL PIN SIZING MACHINE Filed Jan. 13, 1960 3 Sheets-Sheet 2 IN V EN TOR.

Dec. 18, 1962 B. E. RICHARDSON 4 3,068,916

DOWEL PIN SIZING MACHINE Filed Jan. 13, 1960 3 Sheets-Sheet 3 1N VEN TOR.

A 7 TUF/VW United States Patent Ofice 3,068,916 Patented Dec. 18, 1962 3,063,916 DOWEL PIN SIZING MACHINE Bayard E. Richardson, Grand Rapids, Mich.; Curtis V. E. Richardson and Albert B. Doherty III, executors of the estate of Bayard E. Richardson, deceased, assignors t Curtis V. E. Richardson Filed Jan. 13, 1960, Ser. No. 2,223 9 Claims. (Cl. 144-12) This invention relates to improvements in dowel pin sizing machine. The principal objects of this invention are:

First, to provide a power driven automatically operating machine for accurately sizing dowel pins for furniture manufacture.

Second, to provide a dowel pin sizing machine in which a reciprocating plunger forces successive dowel pins through a sizing die and in which individual dowels are sorted automatically and delivered singly to the plunger from an irregular mass of dowels.

Third, to provide a dowel pin aligning and delivering mechanism which will pick up and advance dowels from an irregular mass and deliver them successively in aligned relation to a sizing plunger. j

Fourth, to provide a novel form of separating and aligning hopper for a mass of loose dowels in which an intermittently advanced rotary plate is provided with a series of delivery pockets so that the dowels are rst aligned for entry into the pockets and then advanced for aligned delivery from the pockets while preventing irregular and undesired discharge of dowels through the delivery opening.

Other objects and advantages of the invention will be apparent from a' consideration ofthe following description and claims. The drawings, of which there are three sheets illustrate a highly practical form of the dowel sizing machine. I

FIG. 1 is a fragmentary front side elevational view of the sizing machine of the invention.

FIG. 2 is an' end elevational view of the machine partially broken away in cross section along the plane of the line 2-2 in FIG. l.

FIG. 3 is a fragmentary vertical cross sectional view through the sizing die taken along the plane of the line 3-3 in FIG. 2.

FIG'. 4 is a fragmentary bottom elevational view of the crank case of the machine with the cover'plate of the case removed.

FIG. is a fragmentary cross sectional view through the dowel feeding plunger way taken along the plane of the line 5--5 in FIG. l.

FIG. 6 is a fragmentary cross sectional view taken tangentially through the sorting plate and one of the delivery pockets therein along the plane of the line 6 6 in FIG. 2.

FIG. 7 isa side elevational view of the machine showing thecomplete iluid driving motor. FIG. 8 is a schematic view illustrating the electrical and fluid pressure circuits of the machine.

In the manufacture of fine cabinets and furniture using dowelpin joints, it is essential that the'size ordiameter of the Vdowel pins shall accurately correspond to the dowel pin holes in which they are fitted. Too large a dowel makes it difficult or impossible to insert theA dowel and excludes glue from the dowel hole while too small a dowel creates a'loose weak joint. In the mass production of furniture large numbers of accurately sized dowels are necessary and accurate sizing is essential. vWooden dowels are manufactured and sold to nominal sizes but particularly after they have been stored for some time they no longer maintain the accurate diameter' necessary for ready assembly into a piece of furniture.

The sizing machine of the present invention provides a cylinder hopper 1 mounted with its aXis inclined to the vertical on a base 2 which includes a crank case 3. A shaft 4 rotatably mounted in the crank case is drivingly connected by the cross pin 5 (see FIG. 2) to the hub of a circular feed plate 6 mounted in the bottom of the hopper 1. A downwardly projecting rim 7 on the underside of the feed plate rides on the |bottom 8 of the hopper and provides a frictional drag to prevent overrunning of the feed plate as will be described. A removable cover 9 with a hole 10 in the center permits the hopper to be loaded with a relatively large mass of loose dowel pins of the length and nominal diameter desired.

The feed plate 6 is rotated Within the hopper in a step by stepV motion structure to be described presently. As appears most clearly from FIGS. 2 and 6 the top surface of the feed plate 6 is downwardly inclined towards the thickened rim 7 to provide an upwardly and radially outwardly opening annular groove 11 around the otherwise dat upper surface of the feed plate with the bottom wall of the groove constituting a flange 7 projecting into closely spaced relation with the inside of the hopper 1. 'I'he groove 11 permits the entry of dowel pins into ltangential aligned relation around and below the level of the upper surface of the feed plate and into aligned position in the groove 11. The bottom wall of the groove 11, being part of the plate 6, rotates with the plate and supports dowel pins that fall into the groove. The bottom wall of the groove 11 defines a plurality of angularly spaced feed notches 12 and each of the feed notches is covered by a cover plate 13 projecting radially from the upper surface of the plate so that entry of dowels directly into the feed notches from above is obstructed.

.The cover plates 13 further have downturned ears or stops 14 positioned at the leading ends of the notches 12 so that as the feed plate rotates in a counterclockwise direction as shown in FIGS. l and 7 dowel pins may collect on the bottom of the groove 11 and willA be lifted or advanced around the periphery of the hopper as indicated by the dowel shown in dottled lines at 15 in FIG. 1. As the dowel 15 moves over the top side of the hopper it is free to slide by gravity along the downwardly inclined side of the groove 11 and in so doing it will slide under the next advanced cover plate 13 and into the notch 12 underneath the cover. The individual dowel thuspreceived under one of the covers is confined against escape and is advanced by the trailing edge of the notch 12 until the dowel and notch advance 270 and again arrive at the upper side of the hopper 1. At the desired point the upper side of the hopper is provided with a delivery opening 16 and the single dowel 15 falls through the opening 16 as appears in FIG. 6. The dowel is delivered into a feed chute 17 through which it falls by gravity into a plunger way 18 formed by the two side plates 19 with a V-shaped bottom as appears most clearly in FIG. 5.

An end plate 20 clamped over the ends of the plunger way forming side plates by the bolts 21` carries spaced upper andlower slide plates 22 between which is a horizontally adjustable guide die 23. The guide die 23 has a plurality of tapered guide holes 24 therein which are selectively held in alignment with the end of the plunger way 18 by the retainer pin 25. The holes 24 are of different dimensions to accommodate different nominal sizes of dowel pins. Carried by spacer blocks 26 on the outer side of the guide die 23 is a sizing die plate 27 having a series of different sized sharp edged sizing die openings 28therein. It is pointed out that the centers of the die openings 28 are displaced vertically along a line inclined to correspond to the centers of different sized dowels supported in the .V-shaped bottom of the plunger way 18 (see FIG. 2).

A plunger rod 29 of rectangular cross section disposed on edge is reciprocated through the plunger way 18 to advance individual dowels successively through the guide die holes 24 and the aligned sizing die openings 28. Since the plunger does not advance through the guide die opening, the initial dowel is pushed part way into the sizing die by the plunger and is pushed the rest of the Way through the sizing die by a succeeding dowel. The guide die aligns the dowels with the sizing die and the sharpened edge of the sizing die shaves olf any excess thickness in the size of the dowel as each dowel is passed therethrough. By means of mechanism to be described the advancing motion of the feed plate 6 is timed relative to the operation of the plunger 29 to deliver a dowel onto the top of the plunger 29 as the plunger is advanced in the plunger way. The dowel then falls into flat aligned position in the plunger way as the plunger retracts.

The driving mechanism for the plunger 29 and the feed plate 6 consists of a fluid pressure cylinder 30 having a a piston and piston rod 31 reciprocable therein. The cylinder 30 is mounted at the end of the crank case 3 and the piston rod projects thereinto and is connected directly to the plunger 29. An electrically operated fluid pressure regulating valve 32 mounted on the end of the cylinder 30 has a pair of solenoids 33 and 34 for oppositely shifting the valve to admit uid pressure alternatively through the conduits 35 and 36 to the opposite ends of the cylinder 30 to reciprocate the piston rod and the plunger.

Secured to the plunger 29 and reciprocable therewith within the crank case is a plate 37 (see FIG. 4) having a tappet 38 projecting therefrom to engage and deplace the actuating tappets 39 and 40 of a pair of electrical switches 41 and 42 mounted within a switch case 43 on the side of the crank case. Closing of the switches 41 and 42 alternately actuate the solenoids 33 and 34 to reverse the valve 32 and automatically reciprocate the piston rod 31. Manual switch 44 turns the machine on while the push button switch 45 is provided for energizing the solenoid 33 and retracting the piston rod and plunger in the event that a dowel jammed in the die plates prevents full advance of the lug 38 to the tappet 40.

The plate 37 which reciprocates with the plunger defines a transverse slot 46 in which the crank'pin 47 is slidable. The crank pin is mounted on the oscillating end of a crank arm 48 and the arm is in turn centered on and oscillatable about the lower end of the drive shaft 4 in the crank case. The crank arm 48 carries a spring pressed pawl 49 which is engageable upon advancing motion of the crank arm with the ratchet'50 secured to the shaft 4 by a pin 51 so that advancing motion of the plunger 29 advances the feed plate 6 90. The feed plate and the dowel advancing notches 11 are thus given an intermittent advancing motion timed with the plunger 29 to successively feed dowels to the plunger way as described.

In order to regulate the speed of the iluid pressure cylinder 30 which actuates the plunger rod, a dash pot cylinder 52 is connected to the opposite end of the driving cylinder 30 and the piston rod 31. The dash pot is of the type having a return passage 53 from end to end and a variable valve 54 for regulating .the load or drag applied to the piston rod 31 to control its speed. The valve is a well known type of one way restricting and one way open valve that permits the plunger rod 29 to advance relatively slowly at high pressure but to retract relatively rapidly. This arrangement performs two functions. First, it saves time during the retracting stroke and thus speeds up the operation of the machine. Secondly, it causes the plunger rod 29 to be jerked rapidly from underneath the dowel which has advanced down the chute 17 to lie upon the top of the plunger rod. The inertia of the dowel holds it stationary so that it will `fall flat into the Vspace vacated by the plunger rod rather than being dragged backward with the rod. This prevents rocking and jambing of the dowels in the way 18.

It will be apparent that other driving mechanism for the plunger 29 in place of the reciprocating lluid pressure cylinder 30 may be substituted and still obtain the automatic timed delivery of individual dowels and their powered advance through the sizing die holes 28.

What is claimed as new is:

l. A dowel pin sizing machine comprising a hopper having its axis inclined to the vertical, a circular feed plate rotatably mounted in the bottom of said hopper, means to provide retarding drag 'to the plate, the periphery of the plate being closely spaced from the side of the hopper to prevent dowels falling therebetween and having an upwardly facing annular groove formed therearound to permit dowels to fall in tangential alignment around the plate, a plurality of notches formed in the periphery of said plate through the bottom of said annular groove at equi-angular distances therearound and sized to receive a single dowel to be sized, means connected to advance said plate in step by step manner a distance equal to the spacing between said notches to successively position each notch over a discharge position, covers secured to said plate and projecting over said groove at said notches to Iprevent dowels falling vertically thereinto, projecting stops at the leading ends of said notches, said covers being open at the rear ends of said notches permitting a single dowel to slide from said annular groove into the back of each notch on the downwardly advancing side of said plate, a feed opening formed in the bottom of said hopper at said discharge position, a feed chute positioned under said feed opening and delivering to a plunger way, a plunger way positioned to receive dowels endwise from said feed opening and said feed chute, a driven reciprocating plunger movable through said plunger Way, a guide plate adjustably mounted across the end of said way and having a series of tapered guide holes therein arranged to be selectively centered with various diameter dowels resting in said way, a sizing die carried by said guide plate on `the outer side thereof and having a series of various sized sizing holes formed therein with sharpened edges and aligned with said guide holes, and power means connected to reciprocate said plunger and drive said means to advance said feed plate in timed relation whereby a dowel is delivered to said plunger way on top of the advanced plunger to fall into the way in front of thc plunger upon retraction of the plunger, said power means comprising a fluid actuated piston connected to said plunger, an electrically actuated valve connected to alternately admit tluid pressure to opposite ends of said piston, a tappet reciprocated by said plunger, a pair of electric switches having actuating buttons positioned to be depressed by said tappet at the limits of travel of said tappet, a shaft connected to advance said feed plate and extending transversely adjacent said plunger, a crank oscillatably centered on said shaft and driven by said plunger, a ratchet drivingly connected to said shaft, a spring pressed pawl carried by said crank and engageable with said ratchet to advance said shaft and feed plate, electrical circuits alternately energized by said switches to reversely actuate said valve, and a manually operable switch connected to actuate the valve to retract said piston.

2. A dowel pin sizing machine comprising a hopper having its axis inclined to the vertical, a circular feed plate rotatably mounted in the bottom of said hopper, the periphery of the plate being closely spaced from the side of the hopper to prevent dowels falling therebetween and having an upwardly facing annular groove formed therearound to permit dowels to fall in tangential alignment around the plate, a plurality of notches formed in the periphery of said plate through the bottom of said annular groove at equi-angular distances therearound and sized to receive a single dowel to 4be sized, means conneeted to advance said plate in step by step manner a distance equal to the spacing between said notches to successively position each notch over a discharge position, covers secured to said plate and projecting over said groove at said notches to prevent dowels falling vertically thereinto, projecting stops at the leading ends of said notches, said covers being open at the rear ends of said notches permitting a single dowel to slide from said annular groove into the back of each notch on the downwardly advancing side of said plate, a feed opening formed in the bottom of said hopper at said discharge position, a plunger way positioned to receivedowels endwise from said feed opening, a driven reciprocating plunger movable through said plunger way, a die plate adjustably mounted across the end of said way and having a series of die holes therein larranged to be selectively centered with various diameter dowels resting in said way, and power means connected to reciprocate said plunger and drive said means to advance said feed plate in timed relation whereby a dowel is delivered to said plunger way on top of the advanced plunger to fall into the way in front of the plunger upon retraction of the plunger, said power means comprising a fluid actuated piston connected to said plunger, an electrically actuated valve connected to alternately admit iiuid pressure to opposite ends of said piston, a tappetreciprocated by said plunger, a pair of electric switches having actuating buttons positioned to be depressed by said tappet at the limits of travel of said tappet, a shaft connected to advance said feed plate and extending transversely adjacent said plunger, a crank oscillatably driven by said plunger, a ratchet and pawl drivingly connected between said shaft and said crank to advance said shaft and feed plate, and electrical circuits alternately energized by said switches to reversely actuate said valve.

3. A dowel pin sizing machine comprising a cylindrical hopper having its axis inclined to the vertical and being provided with a cover with a hole in the center, a circular feed plate rotatably mounted in the bottom of said hopper and in frictional engagement with the bottom of the hopper to provide retardingdrag to the plate, the periphery of the plate being closely spaced from the side of the hopper to prevent dowels falling therebetween and having an upwardly facing annular groove formed therearound to permit dowels to fall in tangential alignment around the plate, a plurality of notches formed in the4 periphery of said plate through the bottom of said annular groove at equi-angular distances therearound and sized to receive a single dowel to be sized, means connected to advance said plate in step by step manner a distance equal to thespacing between said notches to successively position each notch over a discharge position at the top of said hopper, covers secured to said plate and projecting over said groove at said notches to prevent dowels falling thereinto axially of the plate and having downwardly projecting stops at the leading ends of said notches to prevent dowels from entering the leading ends of said notches, said covers being open at the rear ends of said notches permitting a single dowel to slide from said annular groove into the back of each notch on the downwardly advancing side of said plate, a feed opening formed in the bottom of said hopper at said discharge position, a feed chute positioned under said feed opening and delivering to a plunger way, a horizontally disposed plunger way positioned to receive dowels endwise from said feed opening and said feed chute, a driven reciprocating plunger movable through said plunger way, a guide plate slidably adjustably mounted across the end of said way and having a series of tapered guide holes therein arranged to be selectively centered with various diameter dowels resting in said way, a sizing die carried by said guide plate on the outer side thereof and having a series of various sized sizing holes formed therein with sharpened edges and aligned with said guide holes, and power means connected to reciprocate said plunger and drive said means to advance said feed plate in timed relation whereby a 6 dowel is delivered to said plunger way on top of the advanced plunger to fall into the way in front of the plunger upon retraction of the plunger.

4. A dowel pin sizing machine comprising a hopper, a circular feed plate mounted to rotate in a plane inclined to the horizontal in the bottom of said hopper, the periphery of the plate having an annular grooveA formed therearound to permit dowels to fall in tangential alignment around the plate, a plurality of notches formed through the bottom of said annular groove at equi-angular distances therearound and sized to receive a `single dowel to -be sized, means connected to advance said plate in step by step manner a distance equal to the spacing between said notches to successively position each notch over a discharge position, covers secured to said plate and projecting over said groove at said notches to prevent dowels falling thereinto axially of the plate and having projecting stops at the leading ends of said notches to prevent dowels from entering the leading ends of said notches, said covers being open at the rear ends of said notches permitting a single dowel to slide from said annular groove into the back of each notch on the downwardly advancing side of said plate, a feed opening formed in said hopper at said discharge position and delivering to a plunger way, a plunger way positioned to receive dowels endwise from said feed opening, a driven reciprocating plunger moveable through said plunger way, a sizing die aligned with said plunger way, and power means connected to reciprocate said plunger and drive said means to advance said feed plate in timed relation whereby a dowel is delivered -to said plunger way in front of the plunger upon retraction of the plunger.

5. A device lfor successively delivering elongated dowel-like objects from an irregularly arranged mass of the objects comprising a feed plate supported to rotate in a plane inclined from the horizontal to have opposite upwardly and downwardly advancing edges, an enclosure positioned to hold said mass `of objects against the upper face of the lower portion of said plate in -said inclined plane, an annular groove formed in said plate around the periphery o-f said face and adapted to receive said objects in alignment tangentially about the plate and below the upper face of the plate, the wall of said enclosure closely embracing said plate and preventing entry of objects between the edge of the plate and the enclosure, a plurality of elongated openings formed in the bottom of said groove at angularly spaced positions therearound and each sized to receive and advance a single one of said objects, a Xed wall closing the bottoms of said openings except at a delivery position located along the periphery of said plate at the upper side of the plate, means connected to rotatably advance said plate in said enclosure, covers on said plate extending over said openings, and stops on said covers located at the leading ends of said openings to prevent entry of objects into the leading ends of said openings and to lift objects in said groove along the upwardly advancing edge of said plate.

6. A device -for successively delivering elongated dowel-like objects from an irregularly arranged mass of the objects comprising a feed plate supported to rotate in a plane inclined from the horizontal to have opposite upwardly and downwardly advancing edges, an enclosure positioned to hold said mass of objects against the upper face of the lower portion of said plate in said inclined plane, an annular groove formed in said plate around the periphery of said face and adapted to receive said objects in alignment tangentially about the plate and below the upper face of the plate, a plurality of elongated openings formed in the bottom of said groove at angularly spaced positions therearound and each sized to receive and advance a single one o-f said objects, a xed wall closing the bottoms of said openings except at a delivery position located along the periphery of said plate, means connected to rotatably advance said plate in said enclosure, covers on said plate extending over said openings, and stops located at the leading ends of said openings to prevent entry of objects into the lea-ding ends of said openings and to lift objects in said groove along the upwardly advancing edge of said plate.

7. A device for successively delivering elongated dowel-like objects from an irregularly arranged mass of the objects comprising a feed plate supported to rtate in a plane inclined from the horizontal to have opposite upwardly and downwar-dly advancing edges, an enclosure positioned to hold said mass of objects against the upper face of the lower portion of said plate in said inclined plane, an annular groove formed in said plate around the periphery of said face and ladapted to re-v ceive said objects in alignment tangentially about the plate, the wall of said enclosure closely embracing said plate and preventing entry of objects between the edge of the plate and the enclosure, a plurality of elongated openings formed in the bottom of said groove at angularly spaced positions therearound and each sized to receive and advance a single one of said objects, a xed wall closing the bottoms of said openings except at a delivery position located along the periphery of said plate, means connected to rotatably advance said plate in said enclosure, covers on said plate extending over said openings, and stops located at the leading ends of said openings to prevent entry of objects into the leading ends of said openings and to lift objects in said groove along the upwardly advancing edge of said plate.

8. A 4device for successively delivering elongated dowel-like objects from an irregularly .arranged mass of the objects comprising a feed plate supported to rotate in a plane inclined from .the horizontal to Ihave opposite upwardly and downwardly advancing edges, an enclosure positioned to hold said ymass of objects against the upper face of the lower portion of said plate in said inclined plane, an annular groove formed in said plate around the periphery of said face and adapted to receive said objects in alignment tangentially about the plate, a plurality of elongated openings formed in the bottom of said groove at angularly spaced positions therearound and each sized to receive and advance a single one of said objects, means closing the bottoms of said openings except at .a delivery position located along the periphery of said plate, means connected to rotatably advance said plate in said enclosure, covers on said plate extending over said openings, and stops located at the leading ends of said openings to prevent entry of objects into the leading ends of said openings and to lift objects in said groove along the upwardly advancing edge of said plate.

9. A device for successively delivering elongated dowel-like objects from an irregularly arranged mass of the objects comprising a feed plate lsupported to rotate in a plane inclined from the horizontal to have opposite upwardly and downwardly advancing edges, an enclosure positioned to hold said mass of objects against the upper face of the lower portion of said plate in said inclined plane, an annular groove formed in said plate around the periphery of said face and adapted to receive said objects in alignment tangentially about the plate, an elongated opening formed in the bottom of said groove and sized to receive and advance a single one of said objects, means closing the bottom of said opening except at a delivery position located along the periphery of said plate, means connected to rotatably advance said plate in said enclosure, a cover on said plate extending over said opening and spaced from the bottom of said grove to provide space for only one object in said opening, and a stop located at the leading end of said opening to prevent entry of objects into the leading end of said opening and to lift objects in said groove along the upwardly advancing edge of said plate.

References Cited in the le of this patent UNITED STATES PATENTS 435,463 Stewart Sept. 2, 1890 1,401,331 lFoote Dec. 27, 1921 2,033,090 Barker Mar. 3, 1936 2,371,126 Best Y Mar. 13, 1945 2,564,944 Witte Aug. 21, 1951 2,619,076 Agin Nov. 25, 1952 2,678,097 Hahn May 11, 1954 

